Leader role not transferred when the inital leader goes offline

[Simon Déziel]

# How to reproduce

1) create a cluster of 3 units:
$ juju deploy ./lxd_ubuntu-20.04-amd64.charm --config mode=cluster -n 2 --to 95,96
$ juju add-unit lxd --to 97

2) take the leader (lxd/78) offline
$ juju ssh lxd/78
$ sudo halt -p

3) wait a little for lxd/78 to loose it's leader status
$ juju status
Model Controller Cloud/Region Version SLA Timestamp
test overlord maas/default 2.9.15 unsupported 19:06:21Z

App Version Status Scale Charm Store Channel Rev OS Message
lxd active 2/3 lxd local 30 ubuntu

Unit Workload Agent Machine Public address Ports Message
lxd/78 unknown lost 95 2602:fc62:b:1018:0:1:0:d agent lost, see 'juju show-status-log lxd/78'
lxd/79 active idle 96 2602:fc62:b:1018:0:1::
lxd/80 active idle 97 2602:fc62:b:1018:0:1:0:12

Machine State DNS Inst id Series AZ Message
95 down 2602:fc62:b:1018:0:1:0:d cloud-vm10 focal default Deployed
96 started 2602:fc62:b:1018:0:1:: cloud-vm01 focal default Deployed
97 started 2602:fc62:b:1018:0:1:0:12 cloud-vm11 focal default Deployed
99 started 2602:fc62:b:1018:0:1:0:9 cloud-vm03 focal default Deployed
101 started 2602:fc62:b:1018:0:1:0:7 cloud-vm02 focal default Deployed
102 started 2602:fc62:b:1018:0:1:0:c cloud-vm04 focal default Deployed
104 started 2602:fc62:b:1018:0:1:0:e cloud-vm12 focal default Deployed
105 started 2602:fc62:b:1018:0:1:0:2 cloud-vm05 focal default Deployed
106 started 2602:fc62:b:1018:0:1:0:3 cloud-vm06 focal default Deployed
107 started 2602:fc62:b:1018:0:1:0:f cloud-vm13 focal default Deployed
108 started 2602:fc62:b:1018:0:1:0:13 cloud-vm14 focal default Deployed
109 started 2602:fc62:b:1018:0:1:0:5 cloud-vm07 focal default Deployed
110 started 2602:fc62:b:1018:0:1:0:6 cloud-vm09 focal default Deployed
111 started 2602:fc62:b:1018:0:1:0:b cloud-vm08 focal default Deployed
112 started 2602:fc62:b:1018:0:1:0:14 cloud-vm15 focal default Deployed

After some time, one would expect a new leader to be elected but that is not the case.

# Additional information
$ juju --version
2.9.16-ubuntu-amd64

[Joseph Phillips (manadart)]

This is addressed by:
https://github.com/juju/juju/pull/13429

[Haw Loeung (hloeung)]

Any ideas which versions of Juju are affected by this bug?

From the initial bug report, that seems to be from 2.9.15?

[Joseph Phillips (manadart)]

I believe it affects 2.9.13 - 2.9.16.